The moons of Uranus might have short-lived atmospheres each time the seasons change. The seasons there are so intense that these tenuous atmospheres, known as exospheres, might exist briefly twice each Uranian 12 months earlier than freezing and falling again all the way down to the floor.

Uranus’s poles are extraordinarily tilted with respect to the planet’s orbit across the solar, which, together with its highly effective magnetic area, makes the seasons there notably excessive. Ben Teolis on the Southwest Analysis Institute in Texas and his colleagues used laboratory experiments on how carbon…